1. Field of the Invention
The present invention relates generally to switchgear for the field of electrical power distribution, and more particularly to switchgear that facilitates most operations without exposure to the high voltage environment adjacent cable terminations and the like.
2. Description of the Related Art
Switchgear are generally categorized by various categories and features such as: installation location (e.g. grade or surface, sub-surface etc.); the configuration of components (e.g. load interrupter switches, fuses, fault interrupters, disconnects, sectionalizers, etc.); the cable connections (e.g. elbows, cable terminators); the accessibility of components and controls; the medium within the switchgear enclosure, for example air, vacuum, oil, gas (such as SF.sub.6), etc.; and additional features such as fault indicators, voltage indicators, power operation, automatic fault interruption control, etc. For example, switchgear that incorporate the combination of a vacuum interrupter with a series connected visible disconnect is disclosed in U.S. Pat. No. 4,484,046 and illustrated in the Square D Bulletin SY-9T (September 1986). In the arrangement of the aforementioned U.S. Pat. No. 4,484,046, the visible disconnect is also connected to a ground when moved to the opened position. Another arrangement, Type RGC switchgear available from ABB and illustrated in Catalog publication N-H 5194 E, utilizes a loadbreak switch and series connected disconnect that is visible and connected to ground in an open position, the loadbreak switch and the disconnect being disposed in an SF.sub.6 environment. Another arrangement disclosed in U.S. Pat. No. 5,508,486 is directed to gas-insulated switchgear having exit passages and a drive device for the internal multi-pole vacuum switch and multi-pole circuit breaker arranged on a front wall of the switchgear housing, the vacuum switching tubes being arranged at right angles to the front wall and the axis of rotation of the switch shaft of the circuit breaker being horizontal and parallel to the front wall of the housing.
While these prior art arrangements may be useful to provide switchgear of various configurations, the prior arrangements are rather awkward to operate and require exposure to the area of the high-voltage cables, do not offer desirable viewing of the open gap of the internal switches, and do not include basic configurations or features that permit the switchgear to be installed in different environments and in different mounting configurations. Switchgear that alleviates many of these drawbacks is shown in U.S. Pat. No. 5,521,567. However, additional operational and structural features would be desirable to enhance the usability and producability of this type of switchgear.